How does a female get rid of belly fat quickly?

Weight loss cannot be targeted to one area of your body (e.g. just your belly); it will come off everywhere, and the rate and order of where it comes off is all down to genes. Crunches will help build up your abdominals but will do nothing to burn the fat in that area. Cardio will help create a calorie deficit to lose weight, this combined with a calorie restricted diet will be your best bet, keep it simple don't be dragged in to all these different weight loss myths like Apples, grapefruits & ice cold water, they make a tiny difference if any to your weight loss. Record what you eat for a week, counting calories yes i know its boring, then at the end of the week once you have a good idea of the amount of calories you generally eat each day, reduce that by 300 calories, as long as what you eat isn't Pizza 24-7 you will be fine and lose weight, whether that's off your stomach straight away or later down the line, it will happen either way. If you miss out on exercise certain days, just restrict your calories slightly more to compensate for it; just make sure to not be over-enthusiastic and restrict them over 500 a day from what you normally eat because this is not healthy.